Environment:

• Cloud provider: AWS
• OS : centos LINUX 7
• Version of Ansible: 2.7.10
• Kubespray version: Master Tag: 2.9.0

Copy of your inventory file:

master-1 ansible_host=ip-10-1-x-x.eu-west-3.compute.internal ip=10.1.x.x
master-2 ansible_host=ip-10-1-x-x.eu-west-3.compute.internal ip=10.1.x.x
worker-1 ansible_host=ip-10-1-x-x.eu-west-3.compute.internal ip=10.1.x.x
worker-2 ansible_host=ip-10-1-x-x.eu-west-3.compute.internal ip=10.1.x.x
worker-3 ansible_host=ip-10-1-x-x.eu-west-3.compute.internal ip=10.1.x.x
worker-4 ansible_host=ip-10-1-x-x.eu-west-3.compute.internal ip=10.1.x.x

[kube-master]
master-1
master-2

[etcd]
master-1
master-2
worker-1

[kube-node]
worker-1
worker-2
worker-3
worker-4

[k8s-cluster:children]
kube-master
kube-node

Command used to invoke ansible:
ansible-playbook -i inventory/moneydev-jordan/inventory.ini cluster.yml -b -v --flush-cache --private-key=~/.ssh/k8s-key.pem --user=centos --extra-vars bootstrap_os=centos

    Output of ansible run:
    TASK [kubernetes/kubeadm : Join to cluster] ***********************************************************************************************************************************************************************
    Wednesday 24 April 2019 12:22:20 +0000 (0:00:00.898) 0:04:40.811 *******
    fatal: [worker-1]: FAILED! => {"changed": false, "msg": "async task did not complete within the requested time"}
    fatal: [worker-3]: FAILED! => {"changed": false, "msg": "async task did not complete within the requested time"}
    fatal: [worker-2]: FAILED! => {"changed": false, "msg": "async task did not complete within the requested time"}
    fatal: [worker-4]: FAILED! => {"changed": false, "msg": "async task did not complete within the requested time"}

logging in to worker nodes and checking logs I found the below

unable to load client CA file /etc/kubernetes/ssl/ca.crt: open /etc/kubernetes/ssl/ca.crt: no such file or directory